From the Abstract: "Early in the COVID-19 [coronavirus disease 2019] pandemic, President Trump imposed travel restrictions on the People's Republic of China (PRC) to slow its spread to the United States. We use the synthetic control method (SCM) under eight different specifications to see whether the travel restrictions slowed the domestic spread of COVID-19. In most specifications, the travel restriction had no effect on the number of COVID-19 cases in the United States. In two specifications, the travel restriction reduced the number of COVID-19 cases for up to 15 days after the ban was enacted. Regardless of the intervention date or how the spread of COVID-19 is measured, we find that the travel restrictions did not delay the prevalence of COVID-19 or did so by 15 days at most."